I am editing a block and want to make a parallel polyline on a different layer. I select the layer, draw the polyline and everything looks ok. When I leave the block editor, however, the whole block (not only the new polyline) is suddenly on the layer I have drawn the parallel polyline on. Exploding the block doesn't change anything. When I enter the block editor again, everything looks the way it should.

I am using parallel polylines to compensate the drill radius, so I want these on a separate layer at all cost. Therefore, this is a major annoyance